The invention relates to an apparatus and method for assembly of mattress spring assemblies, and more particularly, to an apparatus and method for automatically applying clips to borderwires extending about mattress innersprings.
Mattress spring assembly clipping machines are known that automatically apply clips onto borderwires and mattress innersprings that are preassembled via helical wires to form a matrix of innersprings and by clipping the corner innersprings to the borderwires. These known machines use a driven pusher assembly that advances the preclipped mattress spring assemblies along the frame in a ha generally vertical orientation supported by way of an inclined wall. Clip applicator tools are provided at a lower cutout along the wall at a clipping station so that as the spring assembly is advanced between the tools, they are timed to be fired to apply the clips by clinching them about the borderwires and the ends of the innersprings adjacent thereto.
While these vertical-type of automatic clipping machines have proven to be much faster than manual application of the clips as by a worker who holds an applicator tool and positions it for manual firing to apply the clip, a significant limitation on their cycle times is the need to have the borderwires and innersprings in proper orientation relative to each other for clipping to occur successfully. It is generally true that in the preclipped spring assemblies, a good percentage of the inner or coil springs will have their end coils or turns disposed outward beyond the borderwires. However, for clipping to be successful, the end turns of the coil springs need to be disposed inwardly of the borderwires, and accordingly, the automatic clipping machines generally utilize a positioning mechanism to orient the borderwires and end coils in the appropriate clipping orientation. This problem of properly positioning the borderwires and innersprings in their proper clipping orientation can be exacerbated by the wide variety of different sizes and types of mattress spring assemblies that the machine needs to be able to handle. In other words, the machine should be able to clip spring assemblies for twin, full, queen and king size mattresses while also being able to deal with spring assemblies of the same size that have different types, sizes, and numbers of springs used therewith.
In many prior machines, the positioning mechanism utilizes some sort of side pusher device at the clipping station that is activated to push the end turns of the coil springs toward each other and past the borderwires. One significant limitation with these prior positioning mechanisms is that they have to be retracted each time the spring assembly is indexed to the next innerspring for its clipping to avoid interfering with the travel of the spring assembly. As is apparent, this cycle of actuating and retracting the positioning device slows down the entire cycle time for the machine undesirably lowering the production rates that can be obtained therewith.
Another prior machine disclosed in PCT publication WO 97/44275 has spreader pins that are operable to pull the borderwires away from each other and from the end turns of the coil springs. The spreader pins are not retracted after each clip is applied and thus do not cause the problems of the previously-described positioning mechanisms that have to be retracted with each coil that is clipped. However, the pulling action of the spreader pins on the borderwires creates several undesirable problems. First, unlike the coil springs which are specifically designed to be axially compressed, the borderwires are not intended to be pulled apart from each other as contemplated with the ""275 machine. Accordingly, pulling the borderwires apart takes much more force than pushing on the coil springs. Further, where the machine is clipping high density mattress spring assemblies, e.g. 600 coil springs for a full size spring assembly, aligning and fitting the spreader pins between adjacent barrels of the closely spaced coil springs can be highly problematic. Should the spreader pins get caught in a coil spring, the machine will have to be stopped to untangle the spring assembly from the spreader pin(s) with the clipping process then restarted with this downtime slowing down production. In addition, where the coil springs are of the xe2x80x9copen-coilxe2x80x9d variety where their end coils have a cut end so that they are not closed to form a complete circular end coil, it is more likely that the end coil can wrap itself around the borderwire as the mattress assembly is put together via preclipping and moved to the automatic clipping machine. In this instance, pulling the borderwires with the spreader pins can destroy the coil spring having its cut end wrapped about the wire. Another problem is that the operation of the spreader pins too close to the preclipped corner innersprings may weaken or pull the clips off these preclipped corners. In practice it has been found that the machine has to start and stop clipping three or four coils spaced from the preclipped corners to avoid pulling the preclipped end turns apart from the borderwires.
Accordingly, there is a need for a high-speed automatic clip applying machine for mattress spring assemblies. More particularly, there is a need for a high-speed machine that positions the borderwires and coil innersprings in a proper clipping orientation and allows an entire side or end of the spring assembly to be automatically clipped in a highly accurate manner.
In accordance with the present invention, an apparatus and method are provided for applying clips to mattress spring assemblies in a highly accurate and fast manner via operating or positioning members that properly position the innerspring coils relative to the borderwires for clipping thereof, viz. with the end turns of the innerspring coils disposed inwardly relative to adjacent borderwires in a predetermined clipping orientation. Improperly positioned innersprings have their end coils shifted past the borderwires as an incident of being advanced downstream to be clipped by the apparatus and method herein. In this manner, the positioning members are operable to use the progression of the spring assemblies as they are driven downstream in the automatic clipping machine to properly position the innerspring coils relative to the borderwires for being clipped thereto. More particularly, there is at least one positioning member disposed upstream from the clip applicator tool such as in a positioning station that acts to cause the end turns of the mattress innerspring coils as the innersprings move into engagement therewith, to progressively shift into the predetermined clipping orientation that is necessary for proper clipping of the end turns to the borderwires. The positioning member does not have to be cycled between operative and inoperative positions for each clip that is applied thus speeding the overall clipping process for the spring assembly.
In the preferred form, the at least one positioning member includes a lift member that is affixed to the lower support of the clipping machine so that bottoms of portions of the innerspring coils intermediate the end turns thereof ride thereover. As the innerspring intermediate portions engage the lift member and continue their downstream travel, they progressively rise up a ramp surface of the lift member which causes the end turns to be lifted over the borderwires. The at least positioning member further includes cam members that engage the lifted end coils and progressively push them in the transverse direction with continuing downstream travel of the spring assembly. Thus, the lift member raises the end coils to clear the borderwires while at the same time the cam members push the end coils past the borderwires so that they are shifted from an outward disposition relative to the borderwires to the preferred inward disposition relative thereto. It has also been found that the lifting action of the lift member advantageously causes the end turns not riding up the ramp surface to be drawn or canted toward each other due to their attachment in the innerspring matrix via the helical wires, as will be described more fully hereinafter. Accordingly, the lift member can also impart a component of the desired transverse shifting of the end turns.
The lift member is also preferably provided with a down ramp so that the end coils are lowered to the predetermined clipping orientation after they have shifted transversely to be disposed inwardly relative to the borderwires, and the cam members have guide portions that maintain the end coils in their predetermined clipping orientation until they reach the clipping tools. As described above, the lift and cam members do not shift once clipping begins along a side or end of the spring assembly to allow for much more rapid production of clipped spring assemblies with the apparatus and method herein as there is no time wasted for allowing the operating members to undergo cycling for each clip that is applied. Instead, the primary limitation on production speed is the time the spring assembly must be pausing while the clip applicator tools are fired for applying clips about the innerspring end coils and borderwires; accordingly, completely clipped mattress spring assemblies can be produced with the present apparatus and method as fast as the clip applicator tools will allow recognizing that the spring assembly must be stopped as each clip is applied.
Alternatively, the cam members can cooperate with restraining members which keep the borderwires in a substantially fixed position in the transverse direction. This allows the cam member to progressively push the end coils disposed outwardly relative to the adjacent borderwires against and past the restrained borderwire so that the end coils will be disposed inwardly relative to the borderwires in the predetermined clipping orientation. In either instance whether utilizing the lift member to raise the end coils to clear the borderwires or the restraining members to hold the borderwires against transverse shifting, there is no pulling on the borderwires to deflect it transversely and the attendant problems therewith such as in terms of the timing accuracy necessary with activating the pulling members to fit between coils, especially in high density spring assemblies, and having to stop the clipping process prematurely to avoid damaging the preclipped corners.
Accordingly and in one form of the invention, an apparatus for automatically clipping mattress spring assemblies is provided including a frame having portions for supporting spring assemblies in a generally vertical orientation. A drive mechanism advances the spring assemblies in their vertical orientation in a downstream travel direction along the frame portions for being clipped. A clipping tool is provided for securing clips about borderwires and springs for clipping the spring assembly together. There is at least one positioning member upstream from the clipping tool which engages and shifts the innersprings past the borderwires in a direction transverse to the downstream direction as an incident of being advanced in the downstream travel direction. Accordingly, the apparatus herein utilizes the natural progression of the spring assemblies in the downstream travel direction to cause the desired shifting of the innersprings in a direction transverse to the downstream travel direction past the borderwires. The present apparatus avoids pulling on the borderwires as with prior machines and the previously described shortcomings associated therewith.
In a preferred form, the at least one positioning member includes a lift member and an arm member which cooperate to shift the innersprings past the borderwires in the transverse direction as the spring assemblies travel in the downstream direction.
In another form of the invention, a pushing mechanism for an automatic clipping apparatus having a clipping station is provided. The pushing mechanism includes a first portion upstream from the clipping station for engaging innersprings that are not in the desired predetermined clipping orientation relative to the borderwires as the mattress spring assemblies advance in a downstream direction toward the clipping station. The first portion extends in a direction transverse to the downstream direction to push the innersprings past the borderwires in the transverse direction for positioning the innersprings in the predetermined clipping orientation as an incident of being advanced in the downstream direction. A second portion of the pushing mechanism extends from upstream of the clipping station and has an end thereof in the clipping station to keep the innersprings in the predetermined clipping orientation during downstream travel of the spring assembly to the clipping station.
In a preferred form, the first and second portions are integral with each other.
Preferably, the end of the second portion is disposed above a clipping tool in the clipping station. In this manner, the pushing mechanism ensures that the predetermined clipping orientation is maintained until the clip is applied.
In one form, the pushing mechanism is provided in combination with a lifter mechanism for raising the innersprings to clear the borderwires to allow the first portion to push the innersprings in the transverse direction substantially without encountering interference from the borderwires.
In another form, the pushing mechanism is provided in combination with a restraining mechanism for keeping the borderwire in a substantially fixed transverse position as the first portion pushes the innersprings in the transverse direction against and past the borderwires.
In the preferred form of the invention, there is provided a frame, a drive mechanism for advancing spring assemblies downstream along the frame, and applicator tools for securing clips about borderwires at either end turn of the innerspring coil that are in a predetermined clipping orientation relative to each other. A lift member is provided having a ramp surface upwardly inclined in the downstream direction for raising the innersprings so that the end coils clear the borderwires. Arm members are provided having cam portions so that with the arm members in operative positions the cam portions progressively urge engaged end turns of the coils axially toward each other as the spring assembly is advanced in the downstream direction for cooperating with the lift member to shift the end coils toward the predetermined clipping orientation. A controller keeps the arm members in their operative positions without shifting to inoperative positions thereof as the spring assembly is advanced through the clipping station and clips are applied to the unclipped coils along an entire side or end of the spring assembly.
It should be noted that because the mattress spring assemblies are typically preclipped at their corners when referencing that the machine herein clips an entire side or end of the spring assembly, this references the unclipped perimeter coils between the preclipped corner coils along the side or end of the spring assembly.
In one form, a sensor is provided for detecting the spring assembly and sending a signal to the controller for operating the applicator tools and the arm members. The controller upon receiving the sensor signal causes the arm members to shift to their operative positions, the drive mechanism to pause with the borderwires and innersprings in the predetermined clipping orientation at the clipping station, the applicator tools to fire with the arm members maintained in their operative positions, and the drive mechanism to restart to continue advancing the spring assembly downstream.
In another form of the invention, an automatic clip applying apparatus is provided including a frame, a drive mechanism for advancing spring assemblies in a downstream travel direction, and a clipping station including at least one applicator tool. A lifting mechanism is provided upstream of the clipping station for raising portions of the innerspring intermediate the ends thereof to shift the ends past the borderwires in a direction transverse to the downstream direction.
In a preferred form, the apparatus includes a cam member which is actuated to an operative position to push the innersprings past the borderwires in the transverse direction as an incident of the downstream travel of the spring assembly. A sensor detects the spring assembly for shifting the cam member from an inoperative position thereof to its operative position with the cam member staying in the operative position until the drive mechanism has advanced an entire side of the end of the mattress spring assembly past the lifting mechanism.
In yet another form of the invention, an apparatus is provided for automatically applying clips to mattress spring assemblies including borderwires extending about mattress innersprings. The apparatus includes a frame having portions for supporting spring assemblies in a generally vertical orientation. A drive mechanism advances the spring assemblies in their vertical orientation in a downstream travel direction along the frame for being clipped. A clipping station including at least one applicator tool secures clips about borderwires and coils for clipping the spring assembly together. A positioning station is provided upstream from the clipping station and includes at least one operating member which is actuated to an operative position to push the innersprings past the borderwires in a direction transverse to the downstream direction as an incident of being advanced in said downstream travel direction through the positioning station. A sensor detects the spring assembly for shifting the operative member from an inoperative position thereof to its operative position. The operating member stays in the operative position until the drive mechanism has advanced an entire side or end of the mattress spring assembly through the positioning station. In this manner, the apparatus does not slow production by causing its operating member to undergo repeated cycling from inoperative to operative positions thereof while clipping a side or end of the spring assembly. Accordingly, the speed at which the spring assemblies can be driven through the positioning station and the rate of production of completely clipped spring assemblies can be increased with the above-described apparatus.
In one form, the operating member includes an arm having an arcuate portion which engages the innersprings and progressively urges them past the borderwires in the transverse direction as the drive mechanism advances the spring assembly through the positioning station. Preferably, the arm includes a straight portion downstream from the arcuate portion with the arm in the operative position to keep the innerspring pushed past the borderwires as they exit the positioning station.
In another form, the at least one operating member can include at least one finger having an operative position and a restraining portion which keeps the borderwires from being shifted with the pushed innersprings with the finger in the operative position. The finger is advantageous because it does not pull on the borderwire. Instead, the finger serves to guide the borderwire so that it continues to travel in its substantially undeformed state despite the occurrence of the pushing action on the innersprings.
Preferably, the at least one operating member includes a pair of arms mounted relative to the frame so that the mattress spring assembly is advanced between the arms with the respective arms pushing the innersprings in oppositely-directed transverse directions, and a pair of fingers each mounted adjacent one of the arms operable to hold the borderwires in a substantially fixed transverse position as advanced through the positioning station.
In one form, the sensor is disposed upstream of the clipping station, and a controller is provided for receiving a signal from the sensor indicating detection of the spring assembly and using a time delay or distance measurement before actuating the applicator tool for allowing the drive mechanism to advance the spring assembly downstream to the clipping station.
In another aspect of the invention, a method is provided for automatically securing borderwires to innersprings of mattress spring assemblies including providing a preclipped spring assembly having end turns of corner coils clipped to the borderwires, advancing the spring assembly in a substantially vertical orientation in a downstream travel direction so that the coils extend between the ends thereof transverse to the travel direction, progressively shifting the ends of the coils in a direction transverse to the travel direction as the spring assembly advances in the travel direction for orienting the coil ends and borderwires in a predetermined clipping orientation, and clipping the ends of the coils to the borderwires in their predetermined clipping orientation.
In one form, the innerspring ends are progressively shifted in the transverse direction by raising portions of the innersprings intermediate the ends thereof and drawing the innerspring ends toward each other.
In another form, the method includes lifting the coil ends up and over the borderwires to shift the ends toward the predetermined clipping orientation.
In a preferred form, the innerspring ends are progressively shifted in the transverse direction by raising portions of the coils intermediate the ends thereof and pushing the ends in the transverse direction as the spring assembly travels in the downstream direction. Preferably, the method includes lowering the coils so that the ends and borderwires are in the predetermined clipping orientation and guiding the shifted coil ends to maintain the predetermined clipping orientation for clipping.
In one form, the method includes restraining the borderwires from shifting in the transverse direction so that the progressive pushing of the ends of the coils pushes the innerspring ends against and past the restrained borderwires into the predetermined clipping orientation.